1. Field of the Invention
The invention relates to centrifugal pump for liquids, in particular for blood in extracorporeal circulation.
2. Background of the Disclosure
It is known that in extracorporeal blood circuits shunted from a patient, particularly during certain operations, circulation is ensured by a pump which is inserted in the circuit, and the known art essentially provides two types of pump: peristaltic pumps and centrifugal pumps.
Centrifugal pumps essentially comprise a body for the containment of an impeller whereto a magnet is rigidly associated; said magnet is adapted for being rotated, thus rotationally entraining said impeller, by a second rotating magnet contained in a fixed base provided with a seat for the accommodation of said impeller containment body; said centrifugal pumps have considerable functional advantages with respect to peristaltic pumps, in particular as regards safety against high increases in pressure at the outlet end and as regards the possibility of sending air to the patient.
The constructive forms of centrifugal pumps present in the known art, however, are not devoid from disadvantageous characteristics, the first whereof is related to fluid mechanics: the presence of regions in which the blood is stagnant occurs in known pumps, with negative consequences from the point of view of the flow conveyed by the pump and from a strictly medical point of view.
A second disadvantageous characteristic in known centrifugal pumps is furthermore constituted by the presence of sealing gaskets which are adapted for preventing the access of blood to a chamber in which the magnet rigidly associated with the impeller is present; said sealing gaskets, which notoriously constitute a delicate element which is often the source of malfunctions, are arranged in a region in which the flow of liquid is not particularly active, and are therefore in bad functional conditions due to the overheating to which they are subjected.
In known centrifugal pumps, the sterilization operation also has problems, since it is necessary to resort to the adoption of sophisticated sealing gaskets in the method which uses a sterilization gas when one wishes to avoid resorting to the method which uses gamma rays, which compels a selection of special materials.
The aim of the present invention is, therefore, to provide a centrifugal pump for liquids, in particular for blood in extracorporeal circulation, having optimum characteristics from the fluid mechanics point of view and wherein all problems related to liquid tightness are eliminated. Within the scope of the above described aim, the invention is to provide a centrifugal pump suitable for any sterilization treatment without having to resort to particular contrivances.